1. Field of the Invention
The present invention relates generally to an optical device for guiding light to an opto-electrical transducer from a line scanned original image.
2. Description of the Prior Art
A light guide optical device which is used for scanning a storage, or persistent, luminophore as disclosed in U.S. Pat. No. 4,485,302. In an installation for use in x-ray diagnostics, a fluorescent screen having a luminescent storage, or persistent, luminophore as a radiation-sensitive transducer is irradiated with x-rays to store a latent x-ray image. The luminescent storage fluorescent screen forms an original image which is excited to luminescence picture-element-by-picture-element by an additional radiation source, such as a laser, to thereby read out the image using the disclosed light guide optical device as a read-out means. During scanning of a line by the laser beam, light emitted by the fluorescent screen is acquired, or gathered, by the light guide optics at a linear input side. The disclosed light guide member also has an output side which is circularly bent into an annular shape and arranged at an opto-electric transducer, or photodetector. The output signal of the transducer is then supplied to a chain of video processing devices for reproduction of the x-ray picture.
The transition from the linear expanse of the light guide member to the annular, or circular, portion does not ensue abruptly, but gradually, since too great a part of the light would otherwise emerge from the light guide member and the repeated total reflections would be interrupted. The length of the light guide member is relatively great in comparison to the acquired line length. Particularly for short wave length light which is emitted by a storage luminophore, however, additional light losses result from absorption which is proportional to the length of the light guide member. Moreover, the manufacture of the disclosed light guide member is difficult and requires many processing steps.